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I have ddclient running on my server, which is a 12.04 box. My DDNS service is through No-IP. I received an email today from No-IP that my account will be deactivated due to inactivity. I did some more reading because I thought I had ddclient running perfectly, as it's given me no issue for months. Some further research suggests that ddclient creates a cache file, located in /var/cache/ddclient/ddclient.cache. It then checks your IP with some sort of "whatismyip" type of service, and then cross references it versus the cache file. If your IP hasn't changed, it doesn't call out to No-
(Hardware)